Speaker
Description
Dielectric wakefield acceleration, driven by electron beams, generates high-power, narrowband terahertz radiation via the coherent Cherenkov emission. While conventional dielectric-lined waveguides have been studied extensively for fundamental mode excitation, recent theory suggests higher-order modes carrying orbital angular momentum (OAM) can be deliberately excited in modified structures. We present progress toward generation of OAM-carrying THz radiation using tailored drive beam distributions and novel dielectric geometries at the UCLA MITHRA accelerator facility. OAM modes introduce transverse field components with helical wavefronts, enabling simultaneous longitudinal acceleration and transverse focusing of witness beams. This integrated functionality may simplify beamline design and mitigate beam breakup instabilities that currently limit efficiency in wakefield accelerators. We discuss the theoretical framework, particle-in-cell simulation results, experimental configurations, and newly developed diagnostics for OAM mode characterization.
| Working group | WG4 |
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